I have a "A/T 03' G35 SEDAN" currently my check Engine Light turned on, and when rev the car go up to about 1,000 Rpm i hear a knock at the top of the motor..I can feel it with my hand...I have taken it to 2 mechanics and they dont know what it is...Whats odd is the "G" drives fine if i push it hard...I have no performance parts either...any suggestions?
PS:Right now she is going straight to the dealer..

 

First things first- You need to take the car to someone who can pull the code(s) that are causing the light. Autozone or Advance will do it for free.

Oh... the two "mechanics" that looked at the car and did not diagnose the engine light first should not even be allowed to service your lawn mower.

 

just let the dealer take care of it...the tapping or knocking ur feeling could just be parting moving inside the motor, or your injectors firing...

 

Umm... what does the CEL say the problem is?